1. Field of the Invention
The present invention relates to an amplifier used in conjunction with musical instruments such as electric guitars and in particular concerns a circuit for continuously varying the proportion of an input signal fed into a clean channel and into a distorted channel to provide a single combined output signal having varying proportions of clean and dirty amplification.
2. Description of the Related Art
Electric guitars are very popular musical instruments and are capable of producing a wide range of different sounds. In particular, electric guitars can, when used in conjunction with an amplifier, be used to produce a clear sound that is highly reflective of the sound of the strings or the amplifier can be biased so that the sound coming from the amplifier as a result of playing the guitar is distorted. Generally, a distorted sound from an electric guitar results from the amplifier being driven into saturation.
Musicians like to be able to selectively produce either the clean or the distorted sound. Some existing amplifiers have several channels wherein the musician can set a predetermined level of distortion that will be produced by the amplifier in response to the musician playing the instrument. For example, the player may set a channel where a quarter of the sound signal produced is distorted and three quarters is clear. Hence, while playing the musical instrument, the player can select between discreet channels and discreet levels of distortion. In this way, the musician is able to vary the sound produced by the electric guitar.
However, one shortcoming of the prior art electric guitar and amplifier systems is that the changes in the level of distortion are very abrupt. Further, with most existing amplifiers, the number of channels that can be preprogrammed with a proportionate amount of clear and distorted signals is limited, which means that the musician is limited in his or her ability to produce a variety of sounds. Even with the high end amplifiers that have a tremendous number of different channels, there is still an abruptness to transitions between channels.
Hence, there is a need for an amplifier circuit that can be used to continuously switch between different sound characteristics. In particular, with electric guitars, there is a need for an amplifier system that allows the musician to vary the proportion of clean tones and distorted tones emanating from the amplifier while playing the electric guitar over a continuous range.